The present invention relates to a sealed terminal assembly including the electrical cable for use with hermetic compressors. More particularly, the present invention relates to a sealed terminal assembly which effectively seals the connection between the electrical terminal and the cable from moisture and debris including the moisture which the terminal assembly experiences during trans-oceanic shipping.
Prior art terminal assemblies have included both electrical terminals with covers and/or fences which are designed to protect the terminals from physical damage, electrically isolating the terminals for safety concerns and sealing the terminal assemblies from moisture and debris which the terminal assembly is exposed to during its normal operating life. While these prior art terminal assemblies have been effective, there is always a need to improve the sealing of these terminal assemblies. This is especially true for the terminal assemblies on compressors which are shipped by sea. On some trans-oceanic voyages, the compressors are shipped in open crates positioned on the open decks of the cargo vessel. In this shipping position, the compressors and thus the terminal assemblies are subjected to the high humidity of the sea air as well as periodic spraying of salt water on the compressors due to the wave action of the cargo vessel as it proceeds across the ocean.
Typically, a prior art hermetic terminal assembly consists of an electrical terminal and a corresponding electrical cable. The electrical terminal is installed in a hole formed in the hermetic shell of a hermetic compressor so that current may be carried to the motor of the compressor from an external source of power through the corresponding cable where the cable is attached to the electrical terminal. The prior art electric terminals comprise a body welded or secured to the shell of the compressor and a plurality of conductor pins extending through the body. In order to seal and electrically insulate the conductor pins relative to the body, a glass to metal seal is employed, having an epoxy and/or silicone rubber overcoating. A fence normally extends from the hermetic shell and can be integral with the body or it can be a separate component secured to the shell. The fence is designed to protect the electrical terminal and to interface with the corresponding cable to seal the electrical connection between the cable and the electrical terminal from the effects of the external environment.
While these prior art terminal assemblies have been effective in sealing the electrical connection between the cable and the terminal during normal operation of the compressor, a more effective sealing configuration is required for the compressors which are subjected to the open deck shipping environment described above.
The present invention provides the art with a terminal assembly which is capable of protecting the electrical connection between the electrical terminal and the corresponding cable when the compressor is exposed to the environment normally experienced during open deck trans-oceanic shipping. The present invention includes an electrical terminal block which includes a plurality of conductor pins. The terminal block is welded or otherwise secured to a shell of the compressor. A terminal fence is secured to the exterior of the shell in surrounding relationship to the terminal block. An intermediate gasket is placed over the terminal block to provide a seal at the interface with the shell, a seal around the external surface of the terminal block as well as a seal around each individual conductor pin. A power cable is assembled into the terminal bock which makes the necessary electrical connections with the conductor pins and also sealingly engages the power cable with both the intermediate gasket and the terminal fence. Finally, a terminal box cover is placed in sealing relation to the shell and is fixedly secured to the terminal fence. The terminal box cover, the power cable, the terminal fence and the intermediate gasket all cooperate to form a plurality of seals which effectively protect the electrical connections from marine environments.
Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.